The current mobile device market prefers slimmer and more stylish phones. For example, people like phones with a high aspect screen ratio with lots of metals running around and on the back like a metal ring and/or a full metal back. Further, slim designs lead to small and/or tight internal spaces which pose challenges to the antenna engineer as generally more space and clearance are preferred in order to put an antenna with high performance in a mobile phone. Further, with the inclusion of the metal ring or the metal back, the antenna performance will deteriorate. One solution is to use a surrounding metal ring as a main antenna, however, as has been widely publicized, this can also be a big problem: i.e., when such a phone is held in a certain way, the phone can lose signal reception. In another solution, a metal ring can be etched at the bottom of a mobile phone onto a piece of plastic matched in color so that the antenna performance can be preserved.
Apart from the increasing demand for a “better-looking” phone, there can also be standards issues to take into account when designing antennas. For example, in “next generation” LTE (Long Term Evolution) high-speed data transmission networks, mobile devices should include antennas that resonate at frequency bands: 698 MHz-746 MHz and 746 MHz-798 MHz (the LTE700 band). An LTE antenna should hence theoretically have a larger electrical size than a Global System for Mobile Communications)/CDMA (Code Division Multiple Access)/PCS (Personal Communications Service)/UMTS (Universal Mobile Telecommunications System) antenna, since an LTE antenna resonates at a lower frequency. However, with fashion trends of mobile phones being towards “slimmer and lighter”, it is challenging to get a LTE antenna into such trendy devices that still have adequate performance.